Electric cooking device



3 April 26, 1932. w. H. BATHRICK ELECTRIC cooxme DEVICE File d Aug. 1,1930 Jyoti-71in) atloz zzqy Patented Apr. 26, 1932 PATENT OFFICE WALTERH. BATHRIGK, OF BO S'ION, MASSACHUSETTS ELECTRIC COOKING DEVICEApplication filed August 1, 1930. Serial No. 472,214.

My present invention relates to cooking devices, and more particularlyto an lmproved electric cooking device.

My device utilizes the electrical energy and converts it into a maximumconcentration of heat on the objects to be heated or cooked. This isaccomplished by a combination of the well known methods, as conduction,convection and radiation of heat from the heating 1 coils, all of whichare finally concentrated upon a relatively thin metallic plate, orcover, the cover also serving to protect the heating coils and preventshort-circuiting of such coils when liquids are boiled over theircontainers accidentally, as sometimes occurs.

This protection of the coils is also 1mportant even though the coilsmight not be shortcircuited because such liquids usually contaln foodmatter which crystallizes upon the heater elements and to a certaindegree insulate it as Well as other parts of the heat radiatingelements, and reduces the efficiency of the whole unit.

The principal object of my invention, therefore, is an improved electriccooking device. I

Another object is an electric cooking device in which heat conduction,convection and radiation are combined, each assisting the 7 other toproduce an intensely hot cover plate,

thereby materially reducing the amount of electrical current necessaryto produce the desired results.

' Other objects and novel features comprising construction and operationof my device will appear as the description of the invention progresses.

Referring to the drawings: Fig. 1 is a plan view of the heating unitwith the cover removed; Fig. 2 is a cross-section taken on the line 22of Fig. 1;

Fig. 3 is another cross-section taken at 45 right angles to Fig. 2, andindicated at 3-3 on Fig. 1; i

Fig. 4 is a side elevation of one of the wound insulators used in mydevice particularly showing the excessive depth of the 59 wire slots atits top edge purposely provided to facilitate the circulation of hot airunder the cover plate, and

Fig. 5 shows a modified plan view of the heater unit similar to Fig. 1,but using curved insulator bars for the purpose of providing minimumobstruction at the central portion of the bottom of the cover platewhere the reflected heat is the greatest.

Referring more in detail to the drawings, 10 indicates a cup-shapedcasing which may be more or less solidly fixed in an electric cookingrange, its upper edge comprising an outwardly extending flange 11adapted to receive an annular insulator supporting ring 12. The ring 12is provided with a series of slots 13 oppositely opposed on either sideand adapted to receive a series of parallelly arranged insulator bars 14on which are spaced at regular intervals windings of resistance wire 15.

Directly above the bars 14 and contacting with portions thereof, is acover plate 16 preferably made of thin metal, the under side of which isdark in color and non-reflecting. Directly above the supporting ring 12and adjacent the under side of the cover plate 16 isa fiat ring 17 whichmay be permanently attached to the ring 12 by welding or otherwise, thepurpose of which is to retain the insulator bars 14 in place when theunit is being handled, the ring 12, bars 14, and cover 16, comprising aremovable unit. The resistance wire 15 is composed of one continuousWinding, one end of which terminates in a plug socket 18, the other ofwhich similarl terminates in a similar plug socket 19, both sockets, 18and 19, bein attached to the outer casing 10 and having iced wires 20adapted to connect with the house current. The two ends of the wire 15are provided with plugs 21 fitting to sockets 18 and 19 so that when theunit comprising the ring 12, bars 14, and cover 16, are raised, the wire15 may be easily disconnected thereby disconnecting the heat unit fromthe rest of the range. The ring 12 is further provided with a centraltransverse bar 22 provided as a supporting element for the centralportion of the cover 16, the cover being attached to the ring 12 at acentral point in the supporting bar 22. At this point I have provided arectangular slot 23, better shown in Fig. 1, the long sides of thebottom of the slot being slightly beveled as shown in Fig. 2. A screw 24having its tersunk in the cover plate 16, is inserted in the slot 23,the bottom of the screw body 24 being provided with outstandingoppositely opposed beveled sides 25, such that they may resistance wireson the bars 14, air passages 28 are provided for the urpose of allowingthe hot air generated rom the coils an otherwise to circulate under theplate 16, providing proper conditions for heat convection.

The inner surface 30 of the casing consists of a concaved highlypolished surface for the purpose of reflecting and converging theradiant heat 'ven off by the coils and the fiat lower sur ice of therefractory bars upon a smaller central portion of the under s de of thecover 16. The radius of curvature of the concaved surface will bedetermined from an approximate location of the focus point of thereflected heat rays such that the cover plate intercepting the reflectedrays will receive them over a small area. The heat thus concentratedupon the cover plate will be diffused radially through the cover plateboth by conduction and by convection since a slow current of air isbeing assed over the said area. The net result 0 my invention is toproduce a final cover temperature of higher degree for ever watt ofelectrical energy used such that less current is necessary to obtain thedesired cooking heat than would be possible without the combination.Each of the methods here combined namely; conduction from the bars tothe plate, convection from the slow passage of air, and convergedradiation are not acting separately but jointly making an extremelyeflicient and economically operated electrical cooking device with fewor none of the objectionable features sometimes encountered in this typeof device.

Having thus described my invention, what I'clai'm as new, is:

1. An electrical cooking unit comprisin a substantially closed containerhaving a flat top and curved bottom, heating coils attached to the underside of said top adapted to conduct heat thereto, a bright surfacelocated on the inner side of said container adapted to reflect radiantheat against the bottom of said top, an air vent located at the bottomof said bowl, air vents located around head counthe under ed es of saidtop, said air vents adapted to distribute heat by convection to theunderside of said top.

2. In an electrical cooking unit, a cover plate adapted to surmount aconcaved lower casing, resistance wire insulators adapted to contactwith the under side of said cover plate, said insulators provided withslotted edges to receive electrical resistance wire, air gaps located inthe to ,s of said insulators between said wire and t 1e bottom of saidcover plate, an air inlet located in the bottom of said concaved casing,air outlets located ad jacent the lower rim of said cover plate, saidair gaps, inlets, and vents adapted to induce a flow of convectioncurrents radially away from the cover plate center, said casingprovidedwith a olished inner surface for the purpose of re ecting and convergin'radiant heat from said resistance wires an said insulator bars upon asmaller circular ex area of the under side of the said cover plate. 3.In an electrical cooking unit, a cover plate adapted to surmount aconcaved lower casing, resistance wire insulators ada ted to contactwith the under side of sai I cover plate, said insulatorscomprisingrefractorybars havingmid-sections circularly Shaped away fromthe center of said cover member, said insulators provided with slottededges to receive electrical resistance -wire, air gaps located in thetops of said insulators between said wire and the bottom of said coverlate, an air inlet located in. the bottom of said concaved casing, airoutlets located adjacent the lower rim of said cover late, said airgaps, inlets, and vents adapted to induce a flow of convection currentsradially away from the cover plate center, said casing provided with apolished inner surface for the purpose of re ecting and converginradiant heat from said resistances wires and said' insulator bars upon asmaller circular exposed area of the under side of the said cover plate.

In testimony whereof I have aflixed my signature.

WALTER H. BATHRICK.

